Environmental thermal energy conversion

Abstract

A method of electricity production using water thermal energy includes compressing an enclosed working fluid at a first vertical position relative to a surface of a body of water to cause the fluid to move to a second vertical position relative to the surface and subsequently move to the first position in a closed loop, an external environment at the second position having a greater temperature than an external environment at the first position such that the fluid transitions between a liquid phase at the first position and a vapor phase at the second position, the compressing using power from a battery, and expanding the fluid at the second position to generate electricity to charge the battery. The first and second positions may be two depths of the body of water or a height of an atmosphere above the body of water and a depth of the body of water.

What is claimed is: 
     
       1. A method of propelling an apparatus through a body of water using water thermal energy, the method comprising:
 pressurizing an enclosed working fluid to cause the enclosed working fluid to ascend from a first depth to a second depth of a body of water and subsequently descend to the first depth in a closed loop, the water at the second depth having a greater temperature than the water at the first depth such that the enclosed working fluid transitions to a liquid phase in a condenser portion of the closed loop at the first depth and to a vapor phase in a boiler portion of the closed loop at the second depth, the pressurizing done by a pump using power from a battery; 
 expanding the enclosed working fluid through a turbine at the second depth to generate electricity to charge the battery; 
 transitioning an apparatus that houses the closed loop, the pump, and the turbine from a stationary configuration in which a vertical extent of the closed loop extends at least from the first depth to the second depth to a mobile configuration in which the vertical extent of the closed loop is reduced relative to the stationary configuration; and 
 propelling the apparatus through the body of water using power from the battery while the apparatus is in the mobile configuration. 
 
     
     
       2. The method of  claim 1 , further comprising entirely submerging the apparatus in the body of water, the apparatus including a subsurface float. 
     
     
       3. The method of  claim 1 , further comprising partially submerging the apparatus in the body of water, the apparatus including a surface float disposed at the surface of the body of water. 
     
     
       4. The method of  claim 1 , further comprising entirely submerging the apparatus in the body of water, the apparatus having neutral buoyancy. 
     
     
       5. The method of  claim 1 , wherein the apparatus includes an ascending liquid tube in which the enclosed working fluid ascends from the first depth to the second depth and a descending vapor tube in which the enclosed working fluid descends from the second depth to the first depth, the ascending liquid tube and the descending vapor tube being durable enough to avoid buckling or crimping due to pressure of the body of water at the first depth and/or varying currents in the body of water between the first and second depths. 
     
     
       6. The method of  claim 1 , wherein the apparatus includes an ascending liquid tube in which the enclosed working fluid ascends from the first depth to the second depth and a descending vapor tube in which the enclosed working fluid descends from the second depth to the first depth, the ascending liquid tube and the descending vapor tube being capable of flexing to relieve stresses due to varying currents in the body of water between the first and second depths. 
     
     
       7. The method of  claim 1  further comprising intermittently using generated power to charge an external battery installed in an AUV, research platform, or other power-utilizing device. 
     
     
       8. The method of  claim 1 , wherein the transitioning includes coiling, collapsing, or folding the apparatus. 
     
     
       9. The method of  claim 1 , wherein the apparatus includes an ascending liquid tube in which the enclosed working fluid ascends from the first depth to the second depth and a descending vapor tube in which the enclosed working fluid descends from the second depth to the first depth, the method further comprising controlling an amount or height of working fluid in the ascending liquid tube and/or the descending vapor tube using a working fluid reservoir included in the apparatus. 
     
     
       10. A method of electricity production using water thermal energy in a polar region of the earth, the method comprising:
 pressurizing an enclosed working fluid to cause the enclosed working fluid to descend from a first height of an atmosphere above a body of water to a first depth of the body of water and subsequently ascend to the first height in a closed loop, the water at the first depth having a greater temperature than the atmosphere at the first height such that the enclosed working fluid transitions to a liquid phase in a condenser portion of the closed loop at the first height and to a vapor phase in a boiler portion of the closed loop at the first depth, the pressurizing done by a pump using power from a battery; and 
 expanding the enclosed working fluid through a turbine at the first depth to generate electricity to charge the battery. 
 
     
     
       11. The electricity production method of  claim 10 , further comprising cooling the enclosed working fluid at the first height by forced convection. 
     
     
       12. The electricity production method of  claim 10 , further comprising heating the enclosed working fluid at the first depth by forced convection. 
     
     
       13. The electricity production method of  claim 10 , further comprising intermittently charging an AUV or other off-shore power device using power from the battery. 
     
     
       14. The electricity production method of  claim 10 , wherein heat for the expanding comes from thermal energy inside the earth or from nuclear energy. 
     
     
       15. The electricity production method of  claim 10 , further comprising pumping water up from a second depth of the body of water to the first depth, the water at the second depth having a greater temperature than the water at the first depth. 
     
     
       16. The electricity production method of  claim 10 , further comprising:
 housing the closed loop in an apparatus including a descending liquid tube in which the enclosed working fluid descends from the first height to the first depth and an ascending vapor tube in which the enclosed working fluid ascends from the first depth to the first height; and 
 controlling an amount or height of working fluid in the descending liquid tube and/or the ascending vapor tube using a working fluid reservoir included in the apparatus. 
 
     
     
       17. The method of  claim 8 , wherein the apparatus includes an ascending liquid tube in which the enclosed working fluid ascends from the first depth to the second depth and a descending vapor tube in which the enclosed working fluid descends from the second depth to the first depth, and the transitioning includes folding the ascending liquid tube and the descending vapor tube using one or more actuators powered by the battery. 
     
     
       18. The method of  claim 17 , wherein the one or more actuators includes an electrically actuated winch connected to opposing ends of the apparatus by cables. 
     
     
       19. The method of  claim 17 , wherein the apparatus in the mobile configuration is approximately half the length of the apparatus in the stationary configuration. 
     
     
       20. The method of  claim 1 , wherein the transitioning includes reorienting the apparatus to a horizontal position in which the vertical extent of the closed loop is minimized. 
     
     
       21. The method of  claim 1 , wherein the condenser portion includes a condenser comprising a series of tubes. 
     
     
       22. The method of  claim 1 , wherein the boiler portion includes a boiler comprising a series of tubes. 
     
     
       23. The electricity production method of  claim 10 , wherein the condenser portion includes a condenser comprising a series of tubes. 
     
     
       24. The electricity production method of  claim 10 , wherein the boiler portion includes a boiler comprising a series of tubes.